Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

When it is necessary to charge the battery, the following basic rules must be followed:

Tools Required

GM P/N 12303040 GM P/N 1230304

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

1. When charging a battery in the vehicle, proceed to step 2. If you are charging side terminal batteries out of the vehicle, install an adapter kit GM P/N 12303040 . The adapters should be tight against the lead terminals of the battery to keep resistance between the adapter and the battery terminals to a minimum.
2. Make sure all the charger connections are clean and tight.
3. Charge the battery using the charger setting for 12 V batteries that gives the highest charge rate to the battery until the green dot appears. (Do not use the charger settings for jump-starting vehicles to charge the battery. Refer to the charger manufacturer's instructions.) The battery should be checked periodically while charging. Tap the hydrometer lightly on the top to dislodge any air bubbles that may prevent a correct indication.
4. If the battery feels hot, temperature above 53°C (125°F), or if violent gassing or spewing of electrolyte through the vent holes occurs, discontinue charging or reduce the charging rate.
5. After charging, the battery should be tested. Refer to Battery Test Diagnosis .

The time required to charge a battery will vary depending upon the following factors:

1. The size of the battery: A completely discharged, large, heavy-duty battery requires more than twice the recharging time as a completely discharged, smaller battery.
2. The temperature: A longer time is needed to charge any battery at -18°C (0°F) than at 27°C (80°F). When a fast charger is connected to a cold battery, the current accepted by the battery is very low at first. Then, as the battery warms, the battery accepts a higher rate of current.
3. The charging capacity - A charger which can supply only five amperes requires a much longer charging period than a charger that can supply 30 amperes or more.
4. The state-of-charge: A completely discharged battery requires more than twice as much charge time as a half charged battery. Because the electrolyte is nearly pure water and a poor conductor in a completely discharged battery, the battery accepts very low current at first. Later, as the charging current causes the electrolyte acid content to increase, the charging current also increases. Any battery discharged by parasitic loading, and then allowed to stand in this condition for a period of time, may not accept a charge readily. however, if recharged long enough, many batteries will return to a usable condition. If the battery remains in an extremely discharged condition for a prolonged period, it can become permanently damaged. This damage can be accelerated by changes in temperatures. Batteries that are extremely discharged can freeze at temperatures as high as 7°C (20°F), and be permanently damaged. To prevent battery damage and recharge problems, vehicles that are not going to be in service within a 30 day period should have the negative battery cable disconnected to remove the constant drain on the battery. If this is not possible, recharge the battery periodically every 30-45 days until the green dot is visible.